fir.m

数字信号处理基于matlab 文件内容 /conv(卷积部分) dupconv 重叠保留法 freqcirconv 频域圆周卷积 freqconv 频域卷积 timecirconv

function hn = fir(filttype,db,band,w0,w1)
%UNTITLED1 Summary of this function goes here
%  Detailed explanation goes here
%  filttype is 0(lowpas) 1(highpass) 2(bandpass) 
%  db is the stop-band attenuation
%  band is the transition band 
%  w0 is the lp hp w0,or left side of bp.w1 is the right side of bp. 
[wn,d]=getwindow(0,db);
len=ceil(2*pi*d/band);
len=len+mod(len+1,2);
if filttype==2
    hdn=idealfilter(filttype,len,w0,w1);
else 
    hdn=idealfilter(filttype,len,w0);
end
wn=getwindow(len,db);
hn=hdn.*wn';